Juan Manuel Santos takes oath as Colombia's new president

BOGOTA, COLOMBIA -- Eight years ago, homemade rockets fired by Marxist rebels rained down on the presidential palace as Álvaro Uribe took office, forewarning the all-out war that would come in his efforts to take back much of the country from potent guerrilla groups.

On Saturday, Uribe stepped down and Juan Manuel Santos took his place, with the inauguration staged outdoors and the new president speaking of job creation, democratic checks and balances and rural development. It was not until the 34th minute of an hour-long speech that Santos mentioned his commitment to fight the rebels.

The tenor of the day's ceremony reflected the sharp differences in style and substance that seem to be emerging between Uribe, whose government severely weakened the rebels, and Santos, a U.S.-educated technocrat and scion of one of Colombia's most politically influential families.

Since winning the presidency in a June 20 landslide, Santos has marked distance between himself and Uribe, signaling the arrival of a leader who, unlike his predecessor, intends to focus on a social agenda and the country's frayed relations with its neighbors.

"I will preside over a government of national unity that will bring social prosperity for all Colombians," said Santos, 58, delivering his remarks before Latin American leaders and a large delegation of U.S. congressmen. "If we want to have economic and social development, we need to build unity among us."

A former defense minister in the Uribe government, Santos is expected to maintain the same tough approach toward the Revolutionary Armed Forces of Colombia, a waning, hermetic guerrilla group that has bedeviled Colombia since 1964. But Santos is emphasizing the need to address issues that were not priorities during the Uribe era, such as improving Colombia's track record on human rights and seizing tens of thousands of square miles of farmland now in the hands of drug traffickers and corrupt politicians.

The shift could prove beneficial to Colombia by addressing the roots of political violence and helping Colombia gain standing internationally. For the Obama administration, Colombia's closest ally, a less ideological Colombian government more focused on social issues could help Washington improve relations with left-leaning Latin American governments, some of which view the Obama administration with the same suspicion they held for George W. Bush's presidency.

The signals from Santos have stirred hope among lawmakers such as Rep. Jim McGovern (D-Mass.), who has frequently traveled to Colombia and been a stalwart critic of Uribe's governing style. In an interview, he called Santos a "bright, and articulate and capable man."

"For those who've written him off as simply an Uribe clone, they are now pleasantly surprised that he's at least talking about things in a fresh way," McGovern said. "I want to give this guy the benefit of the doubt. He's saying some interesting things."

The new direction, at least on some issues, is particularly apparent in Santos's cabinet.

"These are themes that were not high on the agenda during the Uribe years, and they will now be treated by very competent people who are leading the ministries," said Michael Shifter, president of the Inter-American Dialogue in Washington, who attended the inauguration. "That's a striking contrast with Uribe."